STORY ARCHIVE

West Nile Virus

This is the story of a little Aussie battler who cracked the mystery of deadly virus spreading across America. Dr Roy Hall, once an unknown scientist working on an unremarkable virus called Kunjin, was thrust into the limelight when West Nile Virus unexpectedly hit America and people started to die. Roy came to the rescue identifying the virus, using his science to track it’s alarming progress across the States, and finally developing a vaccine. This is the story of how he did it.

TRANSCRIPT

Narration: In the summer of 1999, a mystery virus hit New York. Several unusual cases of encephalitis – swelling of the brain – started to pop up in the city’s hospitals.

Sufferer 1: I got a rash first and then I got sick

Sufferer 2: They didn’t think I was gonna live

Professor Ian Lipkin: So people have difficulty in concentration, they have headaches, fever, difficulty with paralysis, difficulty breathing.

The patients were originally diagnosed with St Louis Encephalitis but the symptoms didn’t quite add up.

Professor Ian Lipkin: What was different about them was that many of the individuals presented with profound weakness requiring hospitalisation, so it was very unusual encephalitis.

Narration: As summer wore on things became even more confusing. Birds started dying in high numbers, and St Louis Encephalitis doesn’t kill birds. Microbiologist Professor Ian Lipkin was called upon to provide a genetic sequence of the virus.

Professor Ian Lipkin: When we first sequenced the virus we found it was not St Louis Encephalitis, but rather a virus that looked very similar to kunjin virus

Narration: Kunjin is a harmless mosquito borne virus found all the way over in Australia. So could kunjin really have made its way over to America, and could it have turned deadly? Searching for answers the Americans put an internet request out around the world for help. Amazingly, on the other side of the world, in Australia, microbiologist Dr Roy Hall picked up their request. As it turned out he’d spent the last 15 years studying Kunjin virus.

Dr Roy Hall: I think you’d have to say it’s being in the right place at the right time.

Narration: What he’d just discovered was that Kunjin was genetically very closely related to a deadly African disease called West Nile Virus.

Dr Roy Hall: We had just done all the research to find the relationship between Kunjin and West Nile and define that very carefully. Kunjin virus was about to be classified as a part of West Nile yet none of the data really had been put on the major database.

Narration: When Roy saw the request for help on the website he immediately offered to supply his antibody tests to the USA. These tests were vital, they proved the mystery virus was indeed West Nile Virus, which came as a bit of a surprise.

Professor John Mackenzie: Never in my wildest dreams would I have thought West Nile would get to America.

Professor Ian Lipkin: Everybody was surprised, but in retrospect we shouldn’t have been because the world is a very small place.

Narration: West Nile Virus originated in Africa, and has been known to occur in Europe, so how did it get into America?

Dr Roy Hall: The exact mechanism of entry is a mystery. It’s possible that it came in via infected birds that were imported. It is also possible that it came via mosquitoes that were infected and harboured in someone’s luggage or freight.

Narration: But as a mosquito borne disease, it was hoped that when winter hit, that’d be the last America would see of West Nile virus. Unfortunately they couldn’t be more wrong. By 2000 West Nile was spreading into neighbouring states, and with it spread people’s fear of the mosquito.

Professor Ian Lipkin: When the mosquito borne outbreak was first discovered there was a panic. Extensive insecticide spraying got underway and mosquito repellent was flying off the shelf.

Narration: They had to find a way to track the spread of the disease. And again Roy thought he might have the answer.

Dr Roy Hall: Birds are a very important part of the virus lifecycle. Birds are required to pass the virus onto mosquitoes, which then pass the virus onto more birds and that’s the way the virus is transmitted and spread to different parts of the countryside.

Narration: Roy developed a test for use on dead birds that could quickly detect the presence of West Nile Virus.

Dr Roy Hall: This test is now being used by a number of labs in the US. They test on a regular basis serum from wild birds and domestic birds that they take and they can then test to see if these birds contain the antibody to West Nile.

Narration: This tracking system showed the disease really exploded. This is how the epidemic progressed between 1999 and 2001. Where you see the pink areas here, these are the States where there’s activity in 1999. The following year we see in green… And then in 2001 we see this area in blue where the virus spread particularly further south into Florida. And by 2002 West Nile had spread right across America into almost every state.

To date over 200 people have died, and now the race is on to produce a vaccine. Roy and his colleague Alex Khromykh are among the front-runners with a vaccine based on Kunjin virus.

Dr Roy Hall: Based on our studies on the immune response to kunjin virus in mice, that’s enabled us to develop a vaccine that’s effective against kunjin virus and now we find it’s also effective against West Nile.

Narration: It’s working well in the mice and hopefully it will eventually work in people. So if West Nile Virus could take hold of America like this, could it come here? Andrew Van Den Hurk monitors mosquito populations in Australia to see what diseases they’re carrying.

Paul: So what do you use for bait?

Andrew Van Den Hurk: Carbon dioxide, which is our breath.

Narration: He’s about to start looking at whether Australian mosquitoes can carry West Nile Virus.

Andrew Van Den Hurk: We believe there’s a couple of mosquito species in Australia that could transmit the virus.

Narration: But in Australia West Nile would have to compete with Kunjin and Murray Valley encephalitis for hosts and vectors so it wouldn’t sweep the nation like it did in the USA.

Professor John MacKenzie: We wouldn’t see the same spread, the same deaths, same effect in bird species as we’ve seen in America.

Narration: But West Nile has been a wake up call for global disease control.

Professor Ian Lipkin: I think it is a wake up call for humankind, we need to be focused not just on our own backyards, not just on our own species but in terms of thinking about infectious diseases that plague other animals and plague people in portions of our world other than our own

Narration: And for Roy, all his years studying kunjin virus have finally paid off.Dr Roy Hall: I think it’s a very good example of where fundamental research without direct economical applications can provide a very useful answer to some serious problem down the track

Narration: But it was a large dose of good luck that research into kunjin virus gave us the tools to deal with the West Nile outbreak. Next time we may not be so lucky.